This invention relates to pumps and, more particularly, to gerotor pumps having eccentrically aligned rotor gears.
Gerotor pumps comprising eccentrically aligned rotor gears are widely known and used, for example, as fluid pumps. Conventional gerotor pumps typically include an inner rotor having lobes that extend radially outward and an outer rotor that has lobes that extend radially inward. The inner rotor rotates about an eccentric axis relative to the outer rotor to create compression chambers between the lobes of the outer rotor and lobes of the inner rotor. The eccentric rotation decreases the compression chamber size between a low pressure suction side of the pump and a high pressure discharge side of the pump to pump the fluid.
Conventional gerotor pumps have several significant drawbacks. For one thing, it is difficult to maintain a seal between the inner rotor and the outer rotor during operation, especially at low speed, high pressure conditions. This may allow fluid to prematurely escape from the compression chambers, which reduces the pumping efficiency. Additionally, some gerotor pumps that incorporate planetary gears between the rotors do not form seals between the surfaces of the planetary gears and the rotors. Planetary gear gerotor pumps are also susceptible to seizing up when radial forces between the rotors and the planetary gears become too high. As a result, pump maintenance or replacement may be necessary.